If you are trying to get the drawable from the view where the image is set as,

ivshowing.setBackgroundResource(R.drawable.one);

then the drawable will return only null value with the following code...

    drawable = (Drawable) ivshowing.getDrawable();

So, it's better to set the image with the following code, if you wanna retrieve the drawable from a particular view.

 ivshowing.setImageResource(R.drawable.one);

only then the drawable will we converted exactly.

If you are trying to get the drawable from the view where the image is set as,

ivshowing.setBackgroundResource(R.drawable.one);

then the drawable will return only null value with the following code...

   Drawable drawable = (Drawable) ivshowing.getDrawable();

So, it's better to set the image with the following code, if you wanna retrieve the drawable from a particular view.

 ivshowing.setImageResource(R.drawable.one);

only then the drawable will we converted exactly.